U.S. patent application number 10/531705 was filed with the patent office on 2006-06-29 for refrigeration system, compressing and heat-releasing apparatus and heat-releasing device.
This patent application is currently assigned to SHOWA DENKO K.K.. Invention is credited to Yuichi Furukawa, Etsuo Shinmura, Koichiro Take.
Application Number | 20060137385 10/531705 |
Document ID | / |
Family ID | 32179091 |
Filed Date | 2006-06-29 |
United States Patent
Application |
20060137385 |
Kind Code |
A1 |
Take; Koichiro ; et
al. |
June 29, 2006 |
Refrigeration system, compressing and heat-releasing apparatus and
heat-releasing device
Abstract
A refrigeration system including a two-stage type compressor
having independent low-pressure and high-pressure compressing
portions, a heat-releasing device having independent primary and
secondary heat-releasing paths, an expansion valve and a cooler.
The refrigerant primarily compressed by the low-pressure
compressing portion is primarily released in heat by the primary
heat-releasing path. The primarily heat-released refrigerant is
secondarily compressed by the high-pressure compressing portion.
The secondarily compressed refrigerant is secondarily released in
heat by the secondary heat-releasing path to thereby obtain a
low-temperature and high-pressure refrigerant. The low-temperature
and high-pressure refrigerant is decompressed and expanded by an
expansion valve and passes through the cooler to absorb the heat in
a room air, and then returns to the low-pressure compressing
portion of the compressor. In this system, the refrigerant
temperature during the heat-releasing procedure can be kept
low.
Inventors: |
Take; Koichiro; (Oyama-shi,
JP) ; Shinmura; Etsuo; (Oyama-shi, JP) ;
Furukawa; Yuichi; (Oyama-shi, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
SHOWA DENKO K.K.
13-9, Shiba Daimon 1-chome Minato-ku
Tokyo
JP
105-8518
|
Family ID: |
32179091 |
Appl. No.: |
10/531705 |
Filed: |
October 24, 2003 |
PCT Filed: |
October 24, 2003 |
PCT NO: |
PCT/JP03/13614 |
371 Date: |
September 29, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60428921 |
Nov 26, 2002 |
|
|
|
Current U.S.
Class: |
62/498 ;
62/513 |
Current CPC
Class: |
F25B 40/00 20130101;
F25B 2400/072 20130101; F28D 1/05366 20130101; F25B 2309/061
20130101; F25B 9/008 20130101; F25B 2500/18 20130101; F25B 1/10
20130101; F28D 2021/0073 20130101; F28F 2009/0287 20130101; F28D
1/0443 20130101; F25B 2500/01 20130101; F25B 39/04 20130101 |
Class at
Publication: |
062/498 ;
062/513 |
International
Class: |
F25B 1/00 20060101
F25B001/00; F25B 41/00 20060101 F25B041/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 24, 2002 |
JP |
2002-309103 |
Claims
1. A refrigeration system in which compressing and heat-releasing
of a refrigerant by a compressor and a heat-releasing device are
performed in turn repeatedly in a multistage manner to obtain a
low-temperature and high-pressure refrigerant, wherein the
low-temperature and high-pressure refrigerant is decompressed by a
decompressing device, then passes through a cooler to absorb heat
from a medium to be cooled and then returns to the compressor.
2. The refrigeration system as recited in claim 1, wherein the
refrigerant is carbon dioxide (CO.sub.2).
3. A refrigeration system, comprising: a primary compressing
portion that primarily compresses a refrigerant; a secondary
compressing portion that secondarily compresses the refrigerant; a
primary heat-releasing portion that primarily performs
heat-releasing of the refrigerant; a secondary heat-releasing
portion that secondarily performs heat-releasing of the
refrigerant; a decompressing device that decompresses the
refrigerant; and a cooling device that cools a medium to be cooled
by absorbing heat from the medium, wherein the refrigerant
primarily compressed by the primary compressing portion is
primarily released in heat by the primary heat-releasing portion,
the primarily heat-released refrigerant is secondarily compressed
by the secondary compressing portion, the secondarily compressed
refrigerant is secondarily released in heat by the secondary
heat-releasing portion and then passes through the cooling device
to absorb heat from the medium, and then returns to the primary
compressing portion.
4. The refrigeration system as recited in claim 3, wherein the
refrigeration system is provided with a multistage type compressing
device, wherein a first-stage compressing portion of the multistage
compressing device constitutes the primary compressing portion, and
a second-stage compressing portion of the multistage compressing
device constitutes the secondary compressing portion.
5. The refrigeration system as recited in claim 3, wherein the
refrigeration system is provided with a heat-releasing device,
wherein a heat-releasing portion of the heat-releasing device is
divided into two divisional heat-releasing portions, wherein one of
the divisional heat-releasing portions constitutes the primary
heat-releasing portion and the other thereof constitutes the
secondary heat-releasing portion.
6. The refrigeration system as recited in claim 5, wherein a volume
rate of the primary heat-releasing portion with respect to an
entire volume of the heat-releasing portion of the heat-releasing
device is set to be 0.2 to 0.5.
7. The refrigeration system as recited in claim 3, wherein a
compression ratio of the refrigerant by the secondary compressing
portion with respect to a compression ratio of the refrigerant by
the primary compressing portion is set to be 0.5 to 1.5.
8. The refrigeration system as recited in claim 3, further
comprising an intermediate heat exchanger for subcooling the
refrigerant secondarily released in heat by the secondary
heat-releasing portion by exchanging heat with a return traveling
refrigerant flowing out of the cooling device.
9. The refrigeration system as recited in claim 3, wherein carbon
dioxide (CO.sub.2) is used as the refrigerant.
10. A compressing and heat-releasing apparatus equipped with a
multistage compressor, wherein a refrigerant is primarily
compressed by a first-stage compressing portion of the multistage
compressor, the primarily compressed refrigerant is primarily
released in heat by a primary heat-releasing portion, the primarily
heat-released refrigerant is secondarily compressed by a
second-stage compressing portion of the multistage compressor, the
secondarily compressed refrigerant is secondarily released in heat
by a secondary heat-releasing portion, to thereby obtain a
low-temperature and high-pressure refrigerant.
11. The compressing and heat-releasing apparatus as recited in
claim 10, wherein the compressing and heat-releasing apparatus is
provided with a heat-releasing device, wherein a heat-releasing
portion of the heat-releasing device is divided into two divisional
heat-releasing portions, wherein one of the divisional
heat-releasing portions constitutes the primary heat-releasing
portion and the other thereof constitutes the secondary
heat-releasing portion.
12. The compressing and heat-releasing apparatus as recited in
claim 11, wherein a volume rate of the primary heat-releasing
portion with respect to an entire volume of the heat-releasing
portion of the heat-releasing device is set to be 0.2 to 0.5.
13. The compressing and heat-releasing apparatus as recited in
claim 10, wherein a compression ratio of the refrigerant by the
secondary compressing portion with respect to a compression ratio
of the refrigerant by the primary compressing portion is set to be
0.5 to 1.5.
14. The compressing and heat-releasing apparatus as recited in
claim 10, wherein carbon dioxide (CO.sub.2) is used as the
refrigerant.
15. A heat-releasing device provided with a primary heat-releasing
portion for primarily releasing heat of a primarily compressed
refrigerant and a secondary heat-releasing portion for secondary
releasing heat of a secondarily compressed refrigerant after being
primarily released in heat, the heat-releasing device comprising: a
pair of headers; and a plurality of heat exchanging tubes disposed
between the pair of headers arranged in parallel with each other in
a longitudinal direction of the header with opposite ends thereof
being connected to the headers; wherein a refrigerant passing
through the plurality of heat exchanging tubes exchanges heat with
cooling air introduced from a front side of the heat-releasing
device and passing through a gap between adjacent heat exchanging
tubes to be released in heat, wherein each of the headers is
divided by a partitioning member at a same height position to
thereby classify the plurality of heat exchanging tubes into upper
and lower heat exchanging tube groups, one of the heat exchanging
tube group constituting the primary heat-releasing portion and the
other thereof constituting the secondary heat-releasing
portion.
16. The heat-releasing device as recited in claim 15, wherein the
lower heat exchanging tube group constitutes the primary
heat-releasing portion and the upper heat exchanging tube group
constitutes the secondary heat-releasing portion.
17. The heat-releasing device as recited in claim 15,wherein an
inner volume rate of the heat exchanging tubes constituting the
primary heat-releasing portion with respect to an entire inner
volume of the plurality of heat exchanging tubes is set to be 0.2
to 0.5.
18. The heat-releasing device as recited in claim 15,wherein carbon
dioxide (CO.sub.2) is used as the refrigerant.
19. A heat-releasing device provided with a primary heat-releasing
portion for primarily releasing heat of a primarily compressed
refrigerant and a secondary heat-releasing portion for secondarily
releasing heat of a secondarily compressed refrigerant after being
primarily released in heat, the heat-releasing device comprising: a
pair of headers; and a plurality of heat exchanging tubes disposed
between the pair of headers arranged in parallel with each other in
a longitudinal direction of the header with opposite ends thereof
being connected to the headers; wherein a refrigerant passing
through the plurality of heat exchanging tubes exchanges heat with
cooling air introduced from a front side of the heat-releasing
device and passing through a gap between adjacent heat exchanging
tubes to be released in heat, wherein each of the heat exchanging
tubes is provided with a plurality of refrigerant passages arranged
in a tube widthwise direction, wherein each of the pair of headers
is divided by a partitioning member extending in a longitudinal
direction of the header into a front space and a rear space,
whereby the plurality of refrigerant passages of each heat
exchanging tube is classified into a front refrigerant passage
group and a rear refrigerant passage group, one of the refrigerant
passage groups constituting the primary heat-releasing portion and
the other thereof constituting the secondary heat-releasing
portion.
20. The heat-releasing device as recited in claim 19, wherein the
rear refrigerant passage group constitutes the primary
heat-releasing portion and the front refrigerant passage group
constitutes the secondary heat-releasing portion.
21. The heat-releasing device as recited in claim 19,wherein an
inner volume rate of the heat exchanging tubes constituting the
primary heat-releasing portion with respect to an entire inner
volume of the plurality of heat exchanging tubes is set to be 0.2
to 0.5.
22. The heat-releasing device as recited in claim 19,wherein carbon
dioxide (CO.sub.2) is used as the refrigerant.
23. The compressing and heat-releasing apparatus as recited in
claim 11, wherein a compression ratio of the refrigerant by the
secondary compressing portion with respect to a compression ratio
of the refrigerant by the primary compressing portion is set to be
0.5 to 1.5.
24. The compressing and heat-releasing apparatus as recited in
claim 12, wherein a compression ratio of the refrigerant by the
secondary compressing portion with respect to a compression ratio
of the refrigerant by the primary compressing portion is set to be
0.5 to 1.5.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Priority is claimed to Japanese Patent Application No.
2002-309103, filed on Oct. 24, 2002, and U.S. Provisional
Application No. 60/428,921, filed on Nov. 26, 2002, the disclosure
of which are incorporated by reference in their entireties.
[0002] This application is an application filed under 35 U.S.C.
.sctn.111(a) claiming the benefit pursuant to 35 U.S.C.
.sctn.119(e)(1) of the filing date of Provisional Application No.
60/428,921 filed on Nov. 26, 2002 pursuant to 35
U.S.C..sctn.111(b).
TECHNICAL FIELD
[0003] The present invention relates to a refrigeration system
preferably applied to a refrigeration cycle using CO.sub.2
refrigerant, and also relates to a compressing and heat-releasing
apparatus and a heat-releasing device preferably applied to the
refrigeration system.
BACKGROUND ART
[0004] The following description sets forth the inventor's
knowledge of related art and problems therein and should not be
construed as an admission of knowledge in the prior art.
[0005] Conventionally, as a refrigerant for use in a vapor
compression type refrigeration cycle, Freon series refrigerants
were mostly used. In recent years, however, in view of global
environmental conservations, as shown in Japanese Unexamined
Laid-open Patent Publication No. JP2001-82369 A and Japanese
Unexamined Laid-open Patent Publication No. JP2001-99522 A, a
refrigeration cycle using a natural refrigerant such as carbon
dioxide (CO.sub.2) has come to the front.
[0006] As a refrigerant system having a CO.sub.2 refrigerant
refrigeration cycle, for example as shown in FIG. 7, it can be
considered that the refrigerant system is provided with a
compressor 101, a heat-releasing device (radiator) 102, an
intermediate heat exchanger 103, an expansion valve 104, a cooler
105 and an accumulator 106.
[0007] The status of the refrigerant in this in-service
refrigeration system is illustrated in the Mollier diagram shown in
FIG. 8.
[0008] As shown in FIGS. 7 and 8, in this refrigeration cycle, the
refrigerant is compressed by the compressor 101 to be shifted from
the point A to the point B, resulting in a high-temperature and
high-pressure gaseous refrigerant. This gaseous refrigerant passes
through the heat-releasing device 102 to be cooled by the ambient
air to thereby be shifted from the point B to the point C.
Subsequently, this refrigerant passes through the intermediate heat
exchanger 103 to be sub-cooled by exchanging heat with the return
traveling refrigerant, which will be mentioned later, to thereby be
shifted from the point C to the point D. Thereafter, the
refrigerant is decompressed and expanded by the expansion valve 104
to thereby be shifted to the point D to the point E. Then, this
low-temperature and low-pressure refrigerant passes through the
cooler 105 to cool the air in a room by absorbing heat from the
air. On the other hand, the temperature of the refrigerant itself
increases to be shifted from the point E to the point F.
Furthermore, the high-temperature and low-pressure refrigerant
released from the cooler 105 (i.e., the return traveling
refrigerant) is introduced into the accumulator 106 in which only
the gaseous refrigerant is extracted. This return traveling
refrigerant exchanges heat with the aforementioned forward
traveling refrigerant in the intermediate heat exchanger 103 to
further increase the temperature to thereby be shifted from the
point F to the point A. Then, the refrigerant returns to the
compressor 101.
[0009] As explained above, in the refrigeration cycle using
CO.sub.2 as a refrigerant, a supercritical cycle in which the
refrigerant pressure exceeds the critical pressure occurs in the
high-pressure region in the heat-releasing device 102. Thus, the
refrigerant pressure in the high-pressure region becomes higher
than that of a refrigeration cycle using Freon series refrigerant,
and the refrigerant temperature at the inlet portion of the
heat-releasing device becomes higher. Concretely, as shown in the
point B in FIG. 8, the refrigerant becomes a high-temperature state
exceeding 120.degree. C.
[0010] As a result, in cases where an aluminum heat-releasing
device with relatively lower heat resistance, which is used in a
car air-conditioning refrigeration system, is used as the
heat-releasing device 102, there is a possibility that the
heat-releasing device components and the like may receive a bad
influence by the aforementioned high temperature.
[0011] It is an object of the present invention to provide a
refrigeration system capable of solving the problems inherent in
the aforementioned prior art, keeping the refrigerant temperature
lower during the heat-releasing procedure and avoiding harmful
effects due to high temperature on a heat-releasing device or the
like.
[0012] It is another object of the present invention to provide a
compressing and heat-releasing apparatus and a heat-releasing
device used in the aforementioned refrigeration system.
DISCLOSURE OF INVENTION
[0013] In order to attain the aforementioned objects, the present
invention has the following structural features.
[0014] 1. A refrigeration system in which compressing and
heat-releasing of a refrigerant by a compressor and a
heat-releasing device are performed in turn repeatedly in a
multistage manner to obtain a low-temperature and high-pressure
refrigerant, wherein the low-temperature and high-pressure
refrigerant is decompressed by a decompressing device, then passes
through a cooler to absorb heat from a medium to be cooled and then
returns to the compressor.
[0015] In the invention as recited in Item (1) (first aspect of the
invention), since the compressing and heat-releasing of the
refrigerant are performed in turn, the refrigerant temperature can
be kept low. Accordingly, even if an aluminum device is used as the
heat-releasing device, the heat-releasing device never receives a
bad influence due to high temperature, which can assuredly prevent
defects such as thermal deformation or thermal deterioration of the
heat-releasing device. As a result, high reliability and sufficient
durability can be secured.
[0016] Furthermore, in the first aspect of the invention, since the
heat-releasing of the refrigerant is performed stepwise, a
predetermined cooling capacity can be obtained.
[0017] 2. The refrigeration system as recited in Item (1), wherein
the refrigerant is carbon dioxide (CO.sub.2).
[0018] In this system, the refrigerant is limited to CO.sub.2
refrigerant.
[0019] 3. A refrigeration system, comprising: [0020] a primary
compressing portion that primarily compresses a refrigerant; [0021]
a secondary compressing portion that secondarily compresses the
refrigerant; [0022] a primary heat-releasing portion that primarily
performs heat-releasing of the refrigerant; [0023] a secondary
heat-releasing portion that secondarily performs heat-releasing of
the refrigerant; [0024] a decompressing device that decompresses
the refrigerant; and [0025] a cooling device that cools a medium to
be cooled by absorbing heat from the medium, [0026] wherein the
refrigerant primarily compressed by the primary compressing portion
is primarily released in heat by the primary heat-releasing
portion, the primarily heat-released refrigerant is secondarily
compressed by the secondary compressing portion, the secondarily
compressed refrigerant is secondarily released in heat by the
secondary heat-releasing portion and then passes through the
cooling device to absorb heat from the medium, and then returns to
the primary compressing portion.
[0027] According to the invention as recited in Item (3) (second
aspect of the invention), in the same manner as mentioned above,
the heat-releasing device never receives a bad influence due to
high temperature, which can assuredly prevent defects such as
thermal deformation or thermal deterioration of the heat-releasing
device. As a result, high reliability and sufficient durability can
be secured.
[0028] 4. The refrigeration system as recited in Item (3), wherein
the refrigeration system is provided with a multistage type
compressing device, wherein a first-stage compressing portion of
the multistage compressing device constitutes the primary
compressing portion, and a second-stage compressing portion of the
multistage compressing device constitutes the secondary compressing
portion.
[0029] In this system, since the multistage type compressing device
is used to perform compressing twice, the number of parts in a
refrigeration system can be decreased as compared with the case in
which two separate compressors are used, resulting in a compact
refrigeration system. Thus, the refrigeration apparatus can be
decreased in size and weight.
[0030] 5. The refrigeration system as recited in Item (3), wherein
the refrigeration system is provided with a heat-releasing device,
wherein a heat-releasing portion of the heat-releasing device is
divided into two divisional heat-releasing portions, wherein one of
the divisional heat-releasing portions constitutes the primary
heat-releasing portion and the other thereof constitutes the
secondary heat-releasing portion.
[0031] In this system, as compared with the case in which
heat-releasing are performed twice by two separate heat-releasing
devices, the number of parts can be decreased. Thus, the
refrigeration apparatus can be further decreased in size and
weight.
[0032] 6. The refrigeration system as recited in Item (5), wherein
a volume rate of the primary heat-releasing portion with respect to
an entire volume of the heat-releasing portion of the
heat-releasing device is set to be 0.2 to 0.5.
[0033] In this system, a bad influence due to high temperature can
be assuredly prevented, and therefore higher reliability,
sufficient durability and further enhanced cooling capacity can be
secured.
[0034] 7. The refrigeration system as recited in Item (3), wherein
a compression ratio of the refrigerant by the secondary compressing
portion with respect to a compression ratio of the refrigerant by
the primary compressing portion is set to be 0.5 to 1.5.
[0035] In this system, the compressing and heat-releasing of the
refrigerant can be performed effectively, resulting in further
enhanced cooling capacity. In detail, in cases where the
compression ratio of the secondary compressing portion with respect
to the primary compressing portion is too large (larger than 1.5
times), the refrigerant temperature in the secondary heat-releasing
portion becomes high excessively, which causes an extremely low
heat-releasing amount in the primary heat-releasing portion, which
in turn causes a deterioration of the coefficient of performance.
To the contrary, in cases where the compression ratio is too small
(less than 0.5 times), the refrigerant temperature in the primary
heat-releasing portion becomes high excessively, causing an
extremely low heat-releasing amount in the secondary heat-releasing
portion, which in turn causes a deterioration of the heat-releasing
performance and the cooling capacity.
[0036] The compression ratio in the primary compression portion is
defined by "CLo/CLi," where the inlet pressure of the refrigerant
in the primary compressing portion is "CLi(MPa)" and the outlet
pressure of the refrigerant therein is "CLo(MPa)." The compression
ratio in the secondary compression portion is defined by "CHo/CHi,"
where the inlet pressure of the refrigerant in the secondary
compressing portion is "CHi(MPa)" and the outlet pressure of the
refrigerant therein is "CHo(MPa)." Accordingly, in this system, it
is preferable that the compression ratio of the secondary
compressing portion with respect to the primary compressing portion
"(CHo/CHi)/(CLo/CLi)" is set to be 0.5 to 1.5.
[0037] 8. The refrigeration system as recited in Item (3), further
comprising an intermediate heat exchanger for subcooling the
refrigerant secondarily released in heat by the secondary
heat-releasing portion by exchanging heat with a return traveling
refrigerant flowing out of the cooling device.
[0038] In this system, since the refrigerant is subcooled by the
intermediate heat exchanger to increase the heat-releasing amount,
the cooling capacity can be further enhanced.
[0039] 9. The refrigeration system as recited in Item (3), wherein
carbon dioxide (CO.sub.2) is used as the refrigerant.
[0040] In this system, the refrigerant is limited to CO.sub.2
refrigerant.
[0041] The preferable structural features of the second aspect of
the invention as recited in Items (4) to (8) can be employed as
preferable structural features of the below mentioned third to
fifth aspect of the invention.
[0042] 10. A compressing and heat-releasing apparatus equipped with
a multistage compressor, wherein a refrigerant is primarily
compressed by a first-stage compressing portion of the multistage
compressor, the primarily compressed refrigerant is primarily
released in heat by a primary heat-releasing portion, the primarily
heat-released refrigerant is secondarily compressed by a
second-stage compressing portion of the multistage compressor, the
secondarily compressed refrigerant is secondarily released in heat
by a secondary heat-releasing portion, to thereby obtain a
low-temperature and high-pressure refrigerant.
[0043] This invention as recited in Item (10) (third aspect of the
invention) specifies the compressing and heat-releasing device to
be preferably applied to the first and second aspect of the present
invention. By employing this apparatus, the aforementioned
functions and effects can be assuredly obtained.
[0044] In the third aspect of the invention, in the same manner as
mentioned above, it is preferable to employ the following
structural features (11) to (14).
[0045] 11. The compressing and heat-releasing apparatus as recited
in Item (10), wherein the compressing and heat-releasing apparatus
is provided with a heat-releasing device, wherein a heat-releasing
portion of the heat-releasing device is divided into two divisional
heat-releasing portions, wherein one of the divisional
heat-releasing portions constitutes the primary heat-releasing
portion and the other thereof constitutes the secondary
heat-releasing portion.
[0046] 12. The compressing and heat-releasing apparatus as recited
in Item (11), wherein a volume rate of the primary heat-releasing
portion with respect to an entire volume of the heat-releasing
portion of the heat-releasing device is set to be 0.2 to 0.5.
[0047] 13. The compressing and heat-releasing apparatus as recited
in any one of Items (10) to (12), wherein a compression ratio of
the refrigerant by the secondary compressing portion with respect
to a compression ratio of the refrigerant by the primary
compressing portion is set to be 0.5 to 1.5.
[0048] 14. The compressing and heat-releasing apparatus as recited
in Item (10), wherein carbon dioxide (CO.sub.2) is used as the
refrigerant.
[0049] 15. A heat-releasing device provided with a primary
heat-releasing portion for primarily releasing heat of a primarily
compressed refrigerant and a secondary heat-releasing portion for
secondarily releasing heat of a secondarily compressed refrigerant
after being primarily released in heat, the heat-releasing device
comprising: [0050] a pair of headers; and [0051] a plurality of
heat exchanging tubes disposed between the pair of headers arranged
in parallel with each other in a longitudinal direction of the
header with opposite ends thereof being connected to the headers;
[0052] wherein a refrigerant passing through the plurality of heat
exchanging tubes exchanges heat with cooling air introduced from a
front side of the heat-releasing device and passing through a gap
between adjacent heat exchanging tubes to be released in heat,
[0053] wherein each of the headers is divided by a partitioning
member at a same height position to thereby classify the plurality
of heat exchanging tubes into upper and lower heat exchanging tube
groups, one of the heat exchanging tube group constituting the
primary heat-releasing portion and the other thereof constituting
the secondary heat-releasing portion.
[0054] This invention as recited in Item (15) (fourth aspect of the
invention) specifies the heat-releasing device to be preferably
applied to any one of the first to third aspect of the present
invention. By employing this apparatus, the aforementioned
functions and effects can be assuredly obtained.
[0055] 16. The heat-releasing device as recited in Item (15),
wherein the lower heat exchanging tube group constitutes the
primary heat-releasing portion and the upper heat exchanging tube
group constitutes the secondary heat-releasing portion.
[0056] In this heat-releasing device, the heat exchanging
efficiency can be further enhanced. That is, in cases where this
invention is applied to a heat-releasing device in a car
air-conditioner, the lower side of the cooling air to be introduced
into the heat-releasing device is higher in temperature than the
upper side thereof because of various factors such as heat
radiation from the ground. Accordingly, by introducing the lower
air of higher temperature into the primary heat-releasing path at
the higher temperature side and the upper air of lower temperature
into the secondary heat-releasing path at the lower temperature
side, sufficient temperature difference between the refrigerant and
the cooling air can be secured in both the primary and secondary
heat-releasing paths. This enables efficient heat exchanging,
resulting in efficient refrigerant heat-releasing.
[0057] In the fourth aspect of the invention, it is preferable to
employ the following structural features (17) and (18).
[0058] 17. The heat-releasing device as recited in Item (15),
wherein an inner volume rate of the heat exchanging tubes
constituting the primary heat-releasing portion with respect to an
entire inner volume of the plurality of heat exchanging tubes is
set to be 0.2 to 0.5.
[0059] 18. The heat-releasing device as recited in Item (15),
wherein carbon dioxide (CO.sub.2) is used as the refrigerant.
[0060] 19. A heat-releasing device provided with a primary
heat-releasing portion for primarily releasing heat of a primarily
compressed refrigerant and a secondary heat-releasing portion for
secondary releasing heat of a secondary compressed refrigerant
after being primarily released in heat, the heat-releasing device
comprising: [0061] a pair of headers; and [0062] a plurality of
heat exchanging tubes disposed between the pair of headers arranged
in parallel with each other in a longitudinal direction of the
header with opposite ends thereof being connected to the headers;
[0063] wherein a refrigerant passing through the plurality of heat
exchanging tubes exchanges heat with cooling air introduced from a
front side of the heat-releasing device and passing through a gap
between adjacent heat exchanging tubes to be released in heat,
[0064] wherein each of the heat exchanging tubes is provided with a
plurality of refrigerant passages arranged in a tube widthwise
direction, [0065] wherein each of the pair of headers is divided by
a partitioning member extending in a longitudinal direction of the
header into a front space and a rear space, whereby the plurality
of refrigerant passages of each heat exchanging tube is classified
into a front refrigerant passage group and a rear refrigerant
passage group, one of the refrigerant passage groups constituting
the primary heat-releasing portion and the other thereof
constituting the secondary heat-releasing portion.
[0066] This invention as recited in Item (19) (fifth aspect of the
invention) specifies the heat-releasing device to be preferably
applied to any one of the first to third aspect of the present
invention. By employing this apparatus, the aforementioned
functions and effects can be assuredly obtained.
[0067] 20. The heat-releasing device as recited in Item (19),
wherein the rear refrigerant passage group constitutes the primary
heat-releasing portion and the front refrigerant passage group
constitutes the secondary heat-releasing portion.
[0068] In this heat-releasing device, the heat exchanging
efficiency can be further enhanced. That is, the lower-temperature
cooling air which has not yet been passed through any
heat-releasing portion is introduced to the lower-temperature side
secondary heat-releasing portion, and the higher-temperature
cooling air which has been passed through the secondary
heat-releasing means is introduced to the higher-temperature side
primary heat-releasing portion, to thereby releasing heat,
respectively. Thus, in any of the primary and secondary
heat-releasing means, sufficient temperature difference between the
refrigerant and the cooling air can be secured, resulting in
efficient heat exchanging, which enables more efficient
heat-releasing of the refrigerant.
[0069] In the fifth aspect of the invention, in the same manner as
mentioned above, it is preferable to employ the following
structural features (21) and (22).
[0070] 21. The heat-releasing device as recited in Item (19),
wherein an inner volume rate of the heat exchanging tubes
constituting the primary heat-releasing portion with respect to an
entire inner volume of the plurality of heat exchanging tubes is
set to be 0.2 to 0.5.
[0071] 22. The heat-releasing device as recited in Item (19),
wherein carbon dioxide (CO.sub.2) is used as the refrigerant.
[0072] In the refrigeration system of the first and second aspect
of the invention, a bad influence due to high temperature will
never be received. Thus, high reliability and sufficient durability
can be assured. Furthermore, sufficient refrigerant heat-releasing
amount can be secured, resulting in an enhanced cooling
capacity.
[0073] The third to fifth aspect of the invention specifies the
compressing and heat-releasing device or the heat-releasing device
to be preferably applied to the first and second aspect of the
present invention. Therefore, the similar effects in the
aforementioned first and second aspect of the invention can be
assuredly obtained.
[0074] Other objects and the features will be apparent from the
following detailed description of the present invention with
reference to the attached drawings.
[0075] The above and/or other aspects, features and/or advantages
of various embodiments will be further appreciated in view of the
following description in conjunction with the accompanying figures.
Various embodiments can include and/or exclude different aspects,
features and/or advantages where applicable. In addition, various
embodiments can combine one or more aspects or features of other
embodiments where applicable. The descriptions of aspects, features
and/or advantages of particular embodiments should not be construed
as limiting other embodiments or the claims.
BRIEF DESCRIPTION OF DRAWINGS
[0076] FIG. 1 is a refrigerant circuit diagram of a refrigerant
system according to an embodiment of the present invention.
[0077] FIG. 2 is a front view showing a heat-releasing device
applied to the refrigerant system of the embodiment.
[0078] FIG. 3 is a Mollier diagram showing the refrigerant status
in the refrigeration system of the embodiment.
[0079] FIG. 4 is a graph showing the relationship between the
temperature effectiveness and the cooling capacity/the coefficient
of performance in refrigeration systems of the embodiment and a
comparative embodiment.
[0080] FIG. 5 is a graph showing the relationship between the
volume rate of the primary heat-releasing device and the
coefficient of performance in the refrigeration system of the
embodiment.
[0081] FIG. 6 is a graph showing the relationship between the
volume ratio of the primary heat-releasing device and the inlet
refrigerant temperature of the secondary heat-releasing device in
the refrigeration system of the embodiment.
[0082] FIG. 7 is a refrigerant circuit diagram of a refrigerant
system as a background technique.
[0083] FIG. 8 is a Mollier diagram showing the refrigerant status
in the refrigeration system as the background technique.
BEST MODE FOR CARRYING OUT THE INVENTION
[0084] The present invention will be described in detail with
reference to the attached drawings.
[0085] FIG. 1 is a refrigerant circuit diagram of a refrigeration
cycle in a refrigeration system according to an embodiment of the
present invention. As shown in FIG. 1, the refrigeration system of
this embodiment is provided with a multistage compressor 50, a
heat-releasing device 60 as a gas cooler, an intermediate heat
exchanger 71, an expansion valve 72 as a decompressing device, a
cooler 73 such as an evaporator, and an accumulator 74, as
fundamental structural elements.
[0086] The compressor 50 is a two-stage type device provided with a
low-pressure compressing portion 51 as an initial compressing means
and a high-pressure compressing portion 52 as a secondary
compressing means. Both compressing portions 51 and 52 are
constructed independently, and are provided with refrigerant inlets
51a and 52a and refrigerant outlets 51b and 52b, respectively. The
low-pressure compressing portion 51 compresses the refrigerant
introduced via the refrigerant inlet 51a at a low-pressure area and
then lets out the compressed refrigerant via the refrigerant outlet
51b. On the other hand, the high-pressure compressing portion 52
compresses the refrigerant introduced via the refrigerant inlet 52a
at a high-pressure area and then lets out the compressed
refrigerant via the refrigerant outlet 52b.
[0087] As shown in FIG. 2, the heat-releasing device 60 is a
header-type heat exchanger and is provided with a pair of
pipe-shaped header tanks 65 and 65 disposed in parallel with each
other at a certain distance, a plurality of flat heat exchanging
tubes 66 disposed in parallel with each other along the
longitudinal direction (up-and-down direction) of the header tanks
65 with the opposite ends in fluid communication with the header
tanks 65 and 65, and corrugated fins 67 disposed between the
adjacent heat exchanging tubes 66.
[0088] The heat exchanging tube 66 has a plurality of refrigerant
passages disposed in parallel in the widthwise direction (fore and
aft direction), so that refrigerant can passes through each
refrigerant passage. Both of the header tanks 65 and 65 are
provided with partitioning members 65a and 65a at the same
longitudinal position (at the same height), whereby the inside
space of each header tank 65 is divided into an upper space and a
lower space. Thus, the plurality of heat exchanging tubes 66 are
classified into an upper group and a lower group. The lower heat
exchanging tube group located below the partitioning member 65a
forms a primary heat-releasing path 61 as an initial heat-releasing
means, and the upper heat exchanging tube group located above the
partitioning member 65a forms a secondary heat-releasing path 62 as
a secondary heat-releasing means.
[0089] One of the header tanks 65 is provided with refrigerant
inlets 61a and 62a corresponding to the primary and secondary
heat-releasing paths 61 and 62, and the other header tank 65 is
provided with refrigerant outlets 61b and 62b corresponding to the
primary and secondary heat-releasing paths 61 and 62.
[0090] In this heat-releasing device 60, the refrigerant introduced
via the inlets 61a and 62a passes through heat exchanging tubes 66
corresponding to the primary and secondary heat-releasing paths 61
and 62. On the other hand, cooling air introduced from the front
side of the heat-releasing device passes through the gaps between
adjacent heat exchanging tubes 66. Thus, the refrigerant exchanges
heat with the cooling air while passing through each heat
exchanging tube 66 to be cooled (to radiate the heat) and flows out
of the outlets 61b and 62b.
[0091] In this embodiment, each component constituting the
heat-releasing device 60 is made of, for example, aluminum or its
alloy, or an aluminum brazing sheet in which brazing material is
laminated at least one surface thereof. These components are
provisionally assembled into a certain heat exchanger configuration
via brazing materials and temporarily fixed. This provisionally
assembled and temporarily fixed components are brazed in a furnace
at the same time, thereby integrally connecting the entire
components.
[0092] The intermediate heat exchanger 71 exchanges heat between
the forward traveling refrigerant and the return traveling
refrigerant to subcool the forward traveling refrigerant.
[0093] The expansion valve 72 decompresses and expands the
refrigerant, and the cooler 73 cools the room air (a medium to be
cooled) by exchanging the heat of the decompressed and expanded
refrigerant with the heat of the room air.
[0094] Furthermore, the accumulator 74 separates the refrigerant
into a liquefied refrigerant and a gaseous refrigerant to extract
only the gaseous refrigerant.
[0095] In the refrigeration system of this embodiment, the outlet
51b of the low-pressure compressing portion 51 of the compressor 50
is connected to the inlet 61a of the primary heat-releasing path 61
of the heat-releasing device 60, and the outlet 61b of the primary
heat-releasing path 61 is connected to the inlet 52a of the
high-pressure compressing portion 52 of the compressor 50.
[0096] Furthermore, the outlet 52b of the high-pressure compressing
portion 52 is connected to the inlet 62a of the secondary
heat-releasing path 62 of the heat-releasing device 60 and the
outlet 62b of the secondary heat-releasing path 62 is connected to
the forward traveling refrigerant inlet of the intermediate heat
exchanger 71.
[0097] The forward traveling refrigerant outlet of the intermediate
heat exchanger 71 is connected to the inlet side of the expansion
valve 72, and the outlet side of the expansion valve 72 is
connected to the inlet of the cooler 73.
[0098] Furthermore, the outlet of the cooler 73 is connected to the
inlet of the accumulator 74, and the outlet of the accumulator 74
is connected to the return traveling refrigerant inlet of the
intermediate heat exchanger 71.
[0099] The return traveling refrigerant outlet of the intermediate
heat exchanger 71 is connected to the inlet 51a of the low-pressure
compressing portion 51 of the compressor 50.
[0100] This refrigeration system uses CO.sub.2 as a refrigerant,
and can be preferably mounted in a vehicle as an automobile
air-conditioning apparatus or the like.
[0101] In this refrigerant system, as shown in FIG. 3, the
refrigerant is compressed (primarily compressed) by the
low-pressure compressing portion 51 of the compressor 50 to thereby
be shifted from the point A to the point A1.
[0102] Subsequently, the primarily compressed refrigerant passes
through the primary heat-releasing path 61 of the hear releasing
device 60 to be cooled (primarily hear-released) by exchanging heat
with the ambient air (the air to be cooled) to thereby be shifted
from the point A1 to the point A2.
[0103] The primarily heat-released refrigerant is compressed
(secondarily compressed) to the high-pressure state by the
high-pressure compressing portion 52 of the compressor 50 to
thereby be shifted from the point A2 to the point B1.
[0104] The secondarily compressed refrigerant passes through the
secondary heat-releasing path 62 of the hear releasing device 60 to
be cooled (secondarily heat-released) by exchanging the heat with
the ambient air to thereby be shifted from the point B1 to the
point C.
[0105] Subsequently, the secondarily heat-released refrigerant
(forward traveling refrigerant) passes through the intermediate
heat exchanger 71 to be subcooled by exchanging the heat with the
below-mentioned return traveling refrigerant to thereby be shifted
from the point C to the point D.
[0106] Further, the subcooled refrigerant is decompressed and
expanded by the expansion valve 72 to thereby be shifted from the
point D to the point E.
[0107] Then, this low-temperature and low-pressure refrigerant is
introduced into the cooler 73 to cool the room air by absorbing the
heat from the room air (a medium to be cooled). The refrigerant
itself is heated therein to be shifted from the point E to the
point F.
[0108] The enthalpy difference between the point E and the point F
corresponds to the cooling heat quantity and defines the
refrigeration capacity.
[0109] The high-temperature and low-pressure refrigerant heated in
the cooler 73 (return traveling refrigerant) is introduced into the
accumulator 74, and only the gaseous refrigerant is extracted.
[0110] The return traveling refrigerant flowing out of the
accumulator 74 passes through the intermediate heat exchanger 71 to
be heated by exchanging the heat with the aforementioned forward
traveling refrigerant to thereby be shifted from the point F to the
point A, and then returns to the low-pressure compressing portion
51 of the compressor 50.
[0111] In the refrigeration system of this embodiment, since the
compression of the refrigerant and the heat release thereof are
performed in turn, as shown in the point A1 in FIG. 3, the inlet
temperature (maximum temperature) of the refrigerant at the inlet
side of the primary heat-releasing path 61 can be kept at a lower
temperature of 120.degree. C. or below. Accordingly, the aluminum
component materials of the primary heat-releasing device 60 never
receive a bad influence due to high temperature, which assuredly
can prevent defects such as thermal deformation or thermal
deterioration of the heat-releasing device component materials.
This causes high reliability and enough durability.
[0112] Furthermore, since the refrigerant heat-releasing is
performed stepwise in the primary heat-releasing path 61 and then
in the secondary heat-releasing path 62, the predetermined
heat-releasing amount can be assuredly secured, causing sufficient
enthalpy difference within the cooler 73, which in turn can attain
high refrigeration capacity.
[0113] Furthermore, in the refrigeration system of this embodiment,
since the heat-releasing is performed stepwise during the
compression procedures, the refrigerant status in the primary
compression procedure and that in the secondary compression
procedure become near the isothermal curve, i.e., the isothermal
compression status. Therefore, the workload at the time of
compressing decreases, resulting in enhanced coefficient of
performance.
[0114] Furthermore, in the refrigeration system of this embodiment,
since the refrigerant is heat-released by the heat-releasing device
60, and then subcooled (heat-released) by the intermediate heat
exchanger 71 to thereby increase the heat release amount, the
refrigeration performance can be further improved.
[0115] Furthermore, in the refrigeration system of this embodiment,
since the primary and secondary heat-releasing portions 61 and 62
are formed by separating a single heat-releasing device 60 which is
the so-called header type heat exchanger, the number of parts can
be decreased as compared with the case in which heat-releasing is
performed twice by two separate heat-releasing devices, resulting
in a refrigeration apparatus with decreased size and weight.
[0116] Furthermore, in the refrigeration system of this embodiment,
since the multistage (two-stage) compressor 50 having two
compressing portions 51 and 52 is employed to perform the double
compressing, the number of parts can be decreased as compared with
the case in which two separate compressors are employed, resulting
in a refrigeration apparatus with further decreased size and
weight.
[0117] Furthermore, in this embodiment, since the primary
heat-releasing path 61 at the higher temperature side of the
heat-releasing device 60 is located at the lower side of the
secondary heat-releasing path 62 at the lower temperature side of
the heat-releasing device 60, the heat exchanging efficiency can be
further improved because of the following reasons. In cases where
this refrigeration cycle is applied to, for example, a car
air-conditioner, the lower side of the cooling air to be introduced
into the heat-releasing device 60 is higher in temperature than the
upper side thereof because of various factors such as heat
radiation from the ground. Accordingly, by introducing the lower
air of higher temperature into the primary heat-releasing path 61
at the higher temperature side and the upper air of lower
temperature into the secondary heat-releasing path 62 at the lower
temperature side, sufficient temperature difference between the
refrigerant and the cooling air can be secured in both the primary
and secondary heat-releasing paths 61 and 62. This enables
efficient heat exchanging, resulting in efficient refrigerant
heat-releasing.
[0118] In this embodiment, it is preferable that the capacity rate
of the primary heat-releasing path 61 (the total cross-sectional
area of the heat exchanging tubes of the primary path) is set to be
20 to 50% of the entire capacity of the heat-releasing portions of
the heat-releasing device 60, i.e., the total capacity of the
primary and secondary heat-releasing paths 61 and 62 (the total
cross-sectional area of the entire heat exchanging tubes). More
preferably, the upper limit is set to be 30% or less.
[0119] If the capacity rate is too small, it becomes difficult to
obtain enough refrigeration effect because the coefficient of
performance (cooling capacity/compressing power) deteriorates, or
the refrigerant temperature at the inlet 62a of the secondary
heat-releasing path 62 becomes extremely high. To the contrary, if
the capacity ratio becomes too large, the coefficient of
performance deteriorates, which make it difficult to obtain enough
refrigeration effect.
[0120] In the aforementioned heat-releasing device 60, the device
60 is divided in the vertical direction (up-and-down direction)
with respect to the cooling air introduction direction to have the
primary heat-releasing means 61 at the lower side and the secondary
heat-releasing means 62 at the upper side. In place of the above,
in the present invention, the primary heat-releasing means can be
provided at the upper side and the secondary heat-releasing means
can be provided at the lower side.
[0121] Furthermore, in the present invention, as a heat-releasing
means, the so-called multi-flow type heat-releasing means having
refrigerant passages formed into a U-turn or zigzag shape in a
plane perpendicular to the cooling air introducing direction can be
employed.
[0122] Furthermore, in the present invention, the heat-releasing
device can be divided in the cooling air introducing direction to
form a primary heat-releasing path and a secondary heat-releasing
path (primary and secondary heat-releasing means).
[0123] For example, the following structure can be employed. The
inside space of each of the header tanks 65 and 65 is divided into
a frontward space and a rearward space by providing a partitioning
plate within each header tank 65 along the longitudinal direction
of the header tank so that a plurality of refrigerant passages in
each heat exchanging tube 66 connected thereto are classified into
frontward refrigerant passages and rearward refrigerant passages,
one of them constituting a primary heat-releasing path (primary
heat-releasing means) and the other constituting a secondary
heat-releasing path (secondary heat-releasing means).
[0124] In this case, it is preferable that the frontward side of
the tube constituting the upstream side refrigerant passages with
respect to the cooling air introducing direction is the secondary
heat-releasing path (secondary heat-releasing means) and the
rearward side of the tube constituting the downstream side
refrigerant passages with respect to the cooling air introducing
direction is the primary heat-releasing path (primary
heat-releasing means). That is, the lower-temperature cooling air
which has not yet been passed through any heat-releasing portion is
introduced to the lower-temperature side secondary heat-releasing
means, and the higher-temperature cooling air which has been passed
through the secondary heat-releasing means is introduced to the
higher-temperature side primary heat-releasing means, thereby
releasing heat, respectively. Thus, in any of the primary and
secondary heat-releasing means, sufficient temperature difference
between the refrigerant and the cooling air can be secured,
resulting in efficient heat exchanging, which enables more
efficient heat-releasing of the refrigerant.
[0125] Furthermore, in the present invention, primary and secondary
heat-releasing means disposed fore and aft can be formed into the
aforementioned multi-flow type heat-releasing means.
[0126] Furthermore, in the present invention, primary and secondary
heat-releasing means disposed above and below can be divided in the
cooling air introducing direction (fore and aft direction),
respectively, so that each heat-releasing means can be the
so-called counter-flow type having refrigerant passages fore and
aft.
[0127] Furthermore, in the present invention, the installation
direction of the heat-releasing device is not limited to a specific
one. For example, the heat-releasing device can be installed such
that the headers are disposed vertically, horizontally or
obliquely.
[0128] Furthermore, in the aforementioned embodiment, although the
intermediate heat exchanger 71 is disposed at the downstream side
of the heat-releasing device 60, in the present invention, it is
not always necessary to employ this intermediate heat exchanger
71.
[0129] Furthermore, in the aforementioned embodiment, although a
two-stage compressing (heat-releasing) type refrigeration system is
exemplified, the present invention is not limited to it, and can be
applied to a multi-stage (three-stage or more) compressing and
heat-releasing type refrigeration system.
EXAMPLE 1
[0130] In the refrigeration system shown in FIG. 1, the
relationship between the temperature effectiveness of the hear
releasing device 60 and the cooling capacity thereof (kw) and the
relationship between the temperature effectiveness of the
heat-releasing device 60 and the coefficient of performance thereof
(cooling capacity/compressing power) were obtained by computer
simulations, respectively.
Comparative Example
[0131] In the conventional refrigeration system shown in FIG. 7,
the relationship between the temperature effectiveness of the hear
releasing device 102 and the cooling capacity thereof (kw) and the
relationship between the temperature effectiveness of the
heat-releasing device 120 and the coefficient of performance
thereof were obtained by computer simulations, respectively.
[0132] The results of the aforementioned Example 1 and Comparative
Example are shown in the graph of FIG. 4.
[0133] As will be apparent from the graph, the refrigerant system
of Example 1 related to the present invention is superior in both
cooling capacity and coefficient of performance to the refrigerant
system of the Comparative Example.
[0134] Especially, in the two-stage compressing cycle of Example 1,
as mentioned above, since the compressing procedure can be
performed by the isothermal compression, the workload at the time
of compression can be decreased, which in turn can increase the
coefficient of performance.
[0135] To the contrary, in the cycle of Comparative Example, the
temperature increase at the time of compression procedure is large,
resulting in increased workload at the time of compression, which
in turn cause a deterioration of the coefficient of
performance.
[0136] Furthermore, in the cycle of Example 1, even in cases where
the temperature effectiveness of the heat-releasing device is low
(for example, even in cases where it is difficult to secure a
sufficient size of the heat-releasing device), since the inlet side
temperature at the secondary compressing procedure (i.e., the inlet
temperature of the high-pressure compressing portion) is low, the
outlet temperature can be decreased sufficiently, resulting in
sufficient cooling capacity.
[0137] To the contrary, in the cycle of Comparative Example, in
cases where it is difficult to secure a sufficient size of the
heat-releasing device, the outlet side temperature at the
compressing procedure (i.e., the outlet temperature of the
compressing device) cannot be decreased, resulting in insufficient
cooling capacity.
EXAMPLE 2
[0138] In the refrigeration system shown in FIG. 1, the
relationship between the volume rate of the primary heat-releasing
portion 61 with respect to the entire volume of the heat-releasing
portions of the heat-releasing device 60 and the coefficient of
performance was obtained by computer simulations.
[0139] The results are shown in the graph of FIG. 5.
[0140] As will be apparent from the graph, excellent coefficient of
performance can be obtained when the volume rate of the primary
heat-releasing portion 61 falls within the rage of 0.1 to 0.5,
especially 0.3 or less.
EXAMPLE 3
[0141] In the refrigeration system shown in FIG. 1, the
relationship between the volume rate of the primary heat-releasing
portion 61 with respect to the entire volume of the heat-releasing
portions of the heat-releasing device 60 and the inlet temperature
of the secondary heat-releasing portion 62 was obtained by computer
simulations.
[0142] The results are shown in the graph of FIG. 6.
[0143] As will be apparent from the graph, the inlet temperature of
the secondary heat-releasing portion 62 was low in the area in
which the volume rate of the primary heat-releasing portion 61 was
0.2 or more.
[0144] As will be understood from the results of the aforementioned
graphs, in the present invention, it is preferable to set the
volume rate of the primary heat-releasing portion 61 with respect
to the entire volume of the heat-releasing portions to be 0.2 (20%)
to 0.5 (50%), more preferably 0.3 (30%) or less.
[0145] The terms and expressions which have been employed herein
are used as terms of description and not of limitation, and there
is no intent, in the use of such terms and expressions, of
excluding any of the equivalents of the features shown and
described or portions thereof, but it is recognized that various
modifications are possible within the scope of the invention
claimed.
INDUSTRIAL APPLICABILITY
[0146] The refrigeration system, the compressing and heat-releasing
device and the heat-releasing device can be preferably used to, for
example, car air-conditioners, household air-conditioners and
coolers for electronics devices having a refrigeration cycle using
a supercritical refrigerant such as CO.sub.2.
* * * * *